A large family of β-substituted β-lactones, prepared from racemic and optically active malic and alkylmalic acids as precursors, has been used in the synthesis of racemic and optically active polyesters. 1., , , , and 2. These polymeric materials are degradable, bioassimilable and biocompatible. 3. and 4. They can be used in temporary therapeutic applications such as drug delivery systems. In this report, we are investigating the synthesis of more intricate β- ...